CA1280609C - Method of operating blast furnace - Google Patents
Method of operating blast furnaceInfo
- Publication number
- CA1280609C CA1280609C CA000513690A CA513690A CA1280609C CA 1280609 C CA1280609 C CA 1280609C CA 000513690 A CA000513690 A CA 000513690A CA 513690 A CA513690 A CA 513690A CA 1280609 C CA1280609 C CA 1280609C
- Authority
- CA
- Canada
- Prior art keywords
- gas
- blast furnace
- blown
- temperature
- preheating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B5/00—Making pig-iron in the blast furnace
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B5/00—Making pig-iron in the blast furnace
- C21B5/001—Injecting additional fuel or reducing agents
- C21B5/003—Injection of pulverulent coal
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacture Of Iron (AREA)
- Blast Furnaces (AREA)
Abstract
Abstract of the Disclosure According to a method of operating a blast furnace, pure oxygen, pulverized coal, and a temperature control gas which substantially does not contain nitrogen are blown from tuyeres. A preheating gas which substantially does not contain nitrogen is blown from an intermediate shaft level. A blast furnace gas which substantially does not contain nitrogen can be produced from a furnace top.
Description
~ ~a~~
The present invention relates to a method of oper-ating a blast furnace capable of generating a blast furnace gas having a composition suitable as a synthetic chemical industrial gas.
Most blast furnace gases generated in a convention-al blast furnace are consumed in the steel works. ~ow-ever, the amount of gas consumed within such a plant has decreased in recent years in spite of the fact that the amount of blast furnace gas has increased due to the increase in the amount of pig iron manufactured and improvements in plant operation. Therefore, effective utilization of excess blast furnace gases has been a big problem.
It i5 thus assumed that a large amount of CO gas contained in the blast furnace gas can serve as a syn-thetic chemical industrial gas such as a fuel methanol gas.
Conventional blast furnace gas, however, contains a large amount of N2 gas. In order to use the blast fur-nace gas as a synthetic chemical industrial gas, N2 gasmust be separated therefrom, resulting in high cost.
Therefore, it is difficult to use the blast furnace gas as a synthetic chemical industrial gas on an industrial scale.
Japanese Patent Publication No. 37-3356 describes a method of operating a blast furnace wherein oxygen con-taining proper amounts of CO2 gas and H2O steam in place ~,`t 1'~80609 of air is blown from blast furnace tuyères, and at the same time, a reduction gas essentially consisting of CO
and H2 separated from a B gas is blown, thereby setting the content of the reduction gas generated from the top of the furnace at 70%.
This technique aims at decreasing a coke ratio but not at producing a synthetic chemical industrial gas.
This prior-art patent does not describe blowing of a preheating gas from an intermediate shaft level of the blast furnace or blowing of pulverized coal from the tuyères.
Japanese Patent Publication No. 52-32323 describes operations for blowing a top gas regenerated using fos-sil fuel together with oxygen-enriched gas from tuyères, and for blowing the regenerated top gas from an inter-mediate shaft level.
This technique also aims at a decrease in the coke ratio but not at producing a synthetic chemical indus-trial gas. According to this technique, an oxygen-enriched gas is blown, not pure oxygen. Unless nitrogenis removed from the resultant blast furnace gas, it cannot be used as a synthetic chemical industrial gas.
Japanese Patent Publication No. 50-22966 describes an operation wherein a nonoxidizing gas is blown at a temperature of 800C or a temperature higher than that of a charge from a blowing position into a region where the charge temperature is 700C or higher when a shaft ~;~806~)9 furnace operation is performed using a preliminary re-duced charge, thereby preheating the preliminary reduced charge and scrap.
This technique also aims at decreasing the coke ratio, but not at producing a synthetic chemical indus-tial gas. Since pure oxygen is not blown, the blast furnace gas cannot be used as a synthetic chemical in-dustrial gas unless nitrogen is removed therefrom.
Japanese Patent Publication No. 51-8091 describes a technique for controlling oxygen and reduction gas contents to operate a blast furnace when an oxygen-enriched gas and a reduction gas are blown from tuyères.
This technique, however, aims at improving the pro-ductivity of pig iron, but not at producing a synthetic chemical industrial gas~ According to this technique, a preheating gas is not blown from an intermediate shaft level. Since pure oxygen is not blown in the blast fur-nace, nitrogen must be removed from the blast furnace gas if it is to be used as a synthetic chemical indus-trial gas.
It is a first object of the present invention toprovide a method of operating a blast furnace wherein a blast furnace gas, free from nitrogen, can be produced as a synthetic chemical industrial gas while a stable production of pig iron by the blast furnace is main-tained.
It is a second object of the present invention to ~80609 provide a method of operating a blast furnace wherein, even if pure oxygen is blown from tuyères, the theoreti-cal flame temperature at the nose of tuyère is not ex-cessively increased.
It is a third object of the present invention to provide a method of operating a blast furnace wherein a lack of gas in the upper portion of the furnace can be compensated, even if pure oxygen is blown from the tuyères.
It is a fourth object of the present invention to provide a method of operating a blast furnace wherein the amount of coke used can be reduced.
In order to achieve the above objects of the pre-sent invention, pure oxygen is blown from tuyères. A
blast furnace gas generated from the furnace top is con-verted to a gas substantially free from nitrogen. An increase in the theoretical flame temperature at the nose of tuy~re upon blowing of pure oxygen Erom the tuyères can be prevented by blowing a temperature con-trol gas (e.g., steam, water, carbon dioxide, and a blast furnace gas generated from the furnace top) from the tuyères. In addition, the lack of gas in the upper portion at the furnace upon blowing of pure o~ygen from the tuyères can be prevented by blowing from an intermediate shaft level a preheating gas which sub-stantially does not contain nitrogen and used for pre-heating a blast furnace charge, e.g., a gas obtained by 1~8060g combusting the blast furnace gas of the furnace top.
Furthermore, pure oxygen is blown so that pulverized coal can be blown from the tuyères, thereby decreasing the amount of coke in the charge.
The phrase ~blast furnace gas which substantially doez not contain nitrogen" includes a gas containing nitrogen ~normally a concentration of 10~ or less) which does not interfere with operation if it is usea as a chemical gas. The phrase "preheating gas which substan-tially does not contain nitrogen" means a preheating gas containing an amount oE nitrogen small enough to gener-ate the blast furnace gas of the above composition. The term "pure oxygen" means oxygen of high purity contain-ing an amount of nitrogen small enough to generate the blast furnace gas of the above composition.
This invention can be more fully understood from the following detailed description when taken in con-junction with the accompanying drawings, in which:
Fig. 1 is a schematic diagram for explaining an example of a method of operating a blast furnace accord-ing to the present invention;
Fig. 2 is a graph showing the relationship between the concentration of oxygen blown from tuyères and the amount of pulverized coal;
Fig. 3 is a graph showing the relationship between the concentration of oxygen blown from the tuyères and the preheating gas amount; and ~X80~i~9 Fig. 4 is a schematic diagram for explaining an-other example of the method of operating a blast furnace according to the present invention.
Example 1 Fig. 1 is a schematic diagram showing an example of a method of operating a blast furnace according to the present invention. A charge containing iron ore and coke as major constituents is charged into blast furnace 1 from a furnace top or receiving hopper. Pure oxygen 3, pulverized coal 11, H2O (water or steam) 12, and a blast furnace gas as temperature control gas 4' are blown from tuyères 2. Preheating gas 5, which substan-tially does not contain nitrogen, is blown from an intermediate shaft level of the blast furnace to preheat the charge. Coke and pulverized coal are combusted with pure oxygen, iron ore is reduced and melted to produce pig iron and slag, and blast furnace gas 4 which sub-stantially does not contain nitrogen is generated from the furnace top.
Dust is removed from blast furnace gas 4 by dust collector 7. The resultant gas, free from dust, is di-verted to different destinations. A portion is supplied to combustion furnace 9, another portion is supplied as temperature control gas 4' to tuyères 2, another portion is utilized in the steelmaking plant, and the remaining portion is supplied to Co2-separating plant 8. The re-sultant CO and H2 gases are used as a synthetic chemical 806(~3 industrial gas. CO2 gas from CO2-separating plant 8 can be supplied as a temperature control gas to preheating gas generation combustion furnace 9 or tuyères 2.
In the operation method described above, h2O 12 and temperature control gas 4' are blown from tuyères 2 to prevent temperature rise at the nose of tuyère caused by blowing of pure oxygen. The blowing rate is controlled to set a theoretical flame temperature at the nose of tuyère to be 2,000 to 2,600C. Pulverized coal blowing from tuyères 2 is used as a substitute for coke. Ac-cording to the present invention, since pure oxygen is blown from tuyères 2, a large amount of pulverized coal can be blown.
More specifically, when the concentration of oxygen blown from tuyères 2 is increased, the amount of pulver-ized coal is increased, as shown in Fig. 2, although the rate varies according to various conditions such as the type of pulverized coal. Upon an increase in concentra-tion of oxygen blown from the tuyères, an amount of gas flowing through the furnace is decreased. For this reason, the gas must be replenished in the amount to compensate for shortage, as shown in Fig. 3. ~ccording to the present invention, blowing of pure oxygen from the tuyères and the preheating gas from the intermediate shaft level allows blowing of a large amount of pulver-ized coal, e.g., 400 kg/ton of pig iron, and preferably 100 to 400 kg~ton of pig iron. In other words, the amount of coke used in the operation can be greatly reduced.
In order to control the amount of latent heat from the blast furnace, 2 top gas from the tuyères and a blowing rate of H2O are controlled to change a fuel ratio~
Preheating gas 5 is used to increase a gas flow within the furnace and to preheat the charge in the fur-nace. Gas 5 can be generated by combusting the blast furnace gas in combustion furnace 9 with oxygen 3'. The blowing rate of preheating gas 5 is determined by consi~
dering the amount of gas generated at a level below the blowing level such that a thermal flow ratio (solid/gas) preferably falls within the range of 0.8 to 1Ø If the thermal flow ratio is excessively low, a large amount of gas must be blown and its calories are wasted. However, if the thermal flow ratio is excessively high, a short-age of calories within the furnace occurs. The tempera-ture in the furnace is then excessively decreased, and a failure to perform satisfactory gas reduction occurs.
As a result, the furnace operation becomes unstahle.
The preheating gas temperature preferably falls within the range of 500 to 1,200C. If the temperature is ex-cessively low, chemical reduction cannot be sufficiently performed. However, if the temperature is excessively high, the solution loss increases. Therefore, the heat balance at the bottom of the furnace is disturbed, and ~80609 _ 9 the furnace operation becomes unstable. In addition, if iron ore reduction rate is high, the preheatins gas temperature can be set to be low. However, if iron ore reduction rate is low, the preheating gas temperature can be set to be high. Therefore, without delaying the reduction reaction, the calories can be effectively utilized. The preheating gas temperature can be con-trolled by changing a ratio of the blast furnace gas recycled from furnace top to 2 According to the operation method described above, pure oxygen is blown and external N2 gas is substan-tially not introduced to the system. Therefore, the blast furnace gas substantially does not contain N2 gas, therefore N2 need not be separated from the blast furnace gas. Only CO2 gas is separated from the blast furnace gas to be used as a synthetic chemical indus-trial gas, as needed. Therefore, the cost of the gas can be greatly reduced.
The temperature rise at the nose of tuyère or its vicinity upon blowing of pure oxygen can be prevented by blowing the blast furnace gas circulated from the fur-nace top. In addition, the preheating gas blown from the intermediate shaft level prevents a shortage of gas flow, thereby stably operating the blast furnace.
Furthermore, since pulverized coal is blown, the amount of coke used in the furnace can be greatly reduced, thereby reducing the operation cost. A required amount 806(;~3 of blast furnace gas is subjected to CO2 separation when it is used as a synthetic chemical industrial gas, thus further reducing the gas cost.
The operation of the blast furnace according to the present invention will be described with reference to Fig. 1.
Iron ore and coke ta coke ratio of 350 kg/T-HM
or Ton-Hot Metal) were charged into a blast furnace (5,000 t-HM/d or Hot Metal/Day), and pure oxygen (349 Nm3/T), a top gas (165 Nm3/T), pulverized coal (300 kg/T-HM = 21 t/H), and steam (3 kg/T) for pre-venting variations in blast furnace gas composition were blown in the furnace. A preheating gas (1,000C, 105 Nm3/T) was blown from the intermediate shaft portion of the blast furnace. In this case, the preheating gas was produced by combusting the top gas (105 Nm3/T) with oxygen (10 Nm3/T).
The composition of the top gas produced by the blast furnace operation described above was 49% of CO, 33.5% of CO~, 9.2% of H2, 0.73% of H2O, and 0.8~ of N2.
The top gas thus substantially does not contain N2 gas.
The blast furnace gas was passed through the dust-collecter, and the gas without dust was diverted to different destinations. A portion (105 Nm3/T) was blown in the combustion furnace, another portion (165 Nm3/T) was blown from the tuyères, another portion (1,080 Nm3/T, 1,726 KcaQ/Nm3) was used in the steel works, and the ~806(~9 remaining portion was subjected to CO2 separation. The resultant CO and H2 gases were used as a synthetic che-mical industrial gas.
Example 2 Fig 4 shows Example 2 of the method of operating the blast furnace according to the present invention.
Blast furnace operation in Fig. 4 differs from that in Fig. 1 in that CO2 gas, H2O (water or steam), or a gas mixture of CO2 and H2O is blown as temperature control gas 4' from tuyères 2. The CO~ gas is a portion ot the C2 gas from CO2~separating plant 8 and is supplied from C2 supply device 10 to tuyères 2. Another portion of the CO2 gas from CO2-separating plant 8 is supplied to combustion furnace 9 to control the temperature of pre-heating gas 5 generated by combusting the top gas.Example 2 preferably follows the same procedures as in Example 1 and obtains the same effect as therein.
Example 2 will be described with reference to Fig. 4 Iron ore and coke ~a coke ratio of 500 kg/T-~
were charged into a blast furnace (5,000 t-HM~d), and pure oxygen (75,000 Nm3/H), CO2 (40,000 Nm3/H), and pulverized coal (100 kg/T-HM = 21 t/H) were blown from the tuyères. A preheating gas (1,000C, 83,000 Nm3/H 27 x 206 XcaQ/H) was blown from the inter-mediate shaft level. The preheating gas was obtained by combusting a blast furnace gas (14,600 Nm3/H) with 1~8~609 oxygen (5,000 Nm3/H), and the temperature of the pre-heating gas was controlled with CO2 (25,000 Nm3/H).
The composition of the blast furnace gas obtained by the above blast furnace operation was 53~ of CO and 47% of CO2. This blast furnace gas substantially does not contain N2 gas. After the gas was passed through the dust-collecter, a gas portion (14,600 Nm3/H) was blown in the combustion furnace, another gas portion (81,000 Nm3/H, 1~590 KcaQ/Nm3) was used in the steelmak-ing plant, and the remaining portion (135rOOO Nm3/h) wagsubjected CO2 separation and used as a synthetic chemi-cal industrial gas. The CO2 gas obtained upon CO2 se-paration was 25,800 Nm3/H. A predetermined amount of gas was used as a preheating gas temperature control gas 15 and a pulverized coal carrier gas.
The present invention relates to a method of oper-ating a blast furnace capable of generating a blast furnace gas having a composition suitable as a synthetic chemical industrial gas.
Most blast furnace gases generated in a convention-al blast furnace are consumed in the steel works. ~ow-ever, the amount of gas consumed within such a plant has decreased in recent years in spite of the fact that the amount of blast furnace gas has increased due to the increase in the amount of pig iron manufactured and improvements in plant operation. Therefore, effective utilization of excess blast furnace gases has been a big problem.
It i5 thus assumed that a large amount of CO gas contained in the blast furnace gas can serve as a syn-thetic chemical industrial gas such as a fuel methanol gas.
Conventional blast furnace gas, however, contains a large amount of N2 gas. In order to use the blast fur-nace gas as a synthetic chemical industrial gas, N2 gasmust be separated therefrom, resulting in high cost.
Therefore, it is difficult to use the blast furnace gas as a synthetic chemical industrial gas on an industrial scale.
Japanese Patent Publication No. 37-3356 describes a method of operating a blast furnace wherein oxygen con-taining proper amounts of CO2 gas and H2O steam in place ~,`t 1'~80609 of air is blown from blast furnace tuyères, and at the same time, a reduction gas essentially consisting of CO
and H2 separated from a B gas is blown, thereby setting the content of the reduction gas generated from the top of the furnace at 70%.
This technique aims at decreasing a coke ratio but not at producing a synthetic chemical industrial gas.
This prior-art patent does not describe blowing of a preheating gas from an intermediate shaft level of the blast furnace or blowing of pulverized coal from the tuyères.
Japanese Patent Publication No. 52-32323 describes operations for blowing a top gas regenerated using fos-sil fuel together with oxygen-enriched gas from tuyères, and for blowing the regenerated top gas from an inter-mediate shaft level.
This technique also aims at a decrease in the coke ratio but not at producing a synthetic chemical indus-trial gas. According to this technique, an oxygen-enriched gas is blown, not pure oxygen. Unless nitrogenis removed from the resultant blast furnace gas, it cannot be used as a synthetic chemical industrial gas.
Japanese Patent Publication No. 50-22966 describes an operation wherein a nonoxidizing gas is blown at a temperature of 800C or a temperature higher than that of a charge from a blowing position into a region where the charge temperature is 700C or higher when a shaft ~;~806~)9 furnace operation is performed using a preliminary re-duced charge, thereby preheating the preliminary reduced charge and scrap.
This technique also aims at decreasing the coke ratio, but not at producing a synthetic chemical indus-tial gas. Since pure oxygen is not blown, the blast furnace gas cannot be used as a synthetic chemical in-dustrial gas unless nitrogen is removed therefrom.
Japanese Patent Publication No. 51-8091 describes a technique for controlling oxygen and reduction gas contents to operate a blast furnace when an oxygen-enriched gas and a reduction gas are blown from tuyères.
This technique, however, aims at improving the pro-ductivity of pig iron, but not at producing a synthetic chemical industrial gas~ According to this technique, a preheating gas is not blown from an intermediate shaft level. Since pure oxygen is not blown in the blast fur-nace, nitrogen must be removed from the blast furnace gas if it is to be used as a synthetic chemical indus-trial gas.
It is a first object of the present invention toprovide a method of operating a blast furnace wherein a blast furnace gas, free from nitrogen, can be produced as a synthetic chemical industrial gas while a stable production of pig iron by the blast furnace is main-tained.
It is a second object of the present invention to ~80609 provide a method of operating a blast furnace wherein, even if pure oxygen is blown from tuyères, the theoreti-cal flame temperature at the nose of tuyère is not ex-cessively increased.
It is a third object of the present invention to provide a method of operating a blast furnace wherein a lack of gas in the upper portion of the furnace can be compensated, even if pure oxygen is blown from the tuyères.
It is a fourth object of the present invention to provide a method of operating a blast furnace wherein the amount of coke used can be reduced.
In order to achieve the above objects of the pre-sent invention, pure oxygen is blown from tuyères. A
blast furnace gas generated from the furnace top is con-verted to a gas substantially free from nitrogen. An increase in the theoretical flame temperature at the nose of tuy~re upon blowing of pure oxygen Erom the tuyères can be prevented by blowing a temperature con-trol gas (e.g., steam, water, carbon dioxide, and a blast furnace gas generated from the furnace top) from the tuyères. In addition, the lack of gas in the upper portion at the furnace upon blowing of pure o~ygen from the tuyères can be prevented by blowing from an intermediate shaft level a preheating gas which sub-stantially does not contain nitrogen and used for pre-heating a blast furnace charge, e.g., a gas obtained by 1~8060g combusting the blast furnace gas of the furnace top.
Furthermore, pure oxygen is blown so that pulverized coal can be blown from the tuyères, thereby decreasing the amount of coke in the charge.
The phrase ~blast furnace gas which substantially doez not contain nitrogen" includes a gas containing nitrogen ~normally a concentration of 10~ or less) which does not interfere with operation if it is usea as a chemical gas. The phrase "preheating gas which substan-tially does not contain nitrogen" means a preheating gas containing an amount oE nitrogen small enough to gener-ate the blast furnace gas of the above composition. The term "pure oxygen" means oxygen of high purity contain-ing an amount of nitrogen small enough to generate the blast furnace gas of the above composition.
This invention can be more fully understood from the following detailed description when taken in con-junction with the accompanying drawings, in which:
Fig. 1 is a schematic diagram for explaining an example of a method of operating a blast furnace accord-ing to the present invention;
Fig. 2 is a graph showing the relationship between the concentration of oxygen blown from tuyères and the amount of pulverized coal;
Fig. 3 is a graph showing the relationship between the concentration of oxygen blown from the tuyères and the preheating gas amount; and ~X80~i~9 Fig. 4 is a schematic diagram for explaining an-other example of the method of operating a blast furnace according to the present invention.
Example 1 Fig. 1 is a schematic diagram showing an example of a method of operating a blast furnace according to the present invention. A charge containing iron ore and coke as major constituents is charged into blast furnace 1 from a furnace top or receiving hopper. Pure oxygen 3, pulverized coal 11, H2O (water or steam) 12, and a blast furnace gas as temperature control gas 4' are blown from tuyères 2. Preheating gas 5, which substan-tially does not contain nitrogen, is blown from an intermediate shaft level of the blast furnace to preheat the charge. Coke and pulverized coal are combusted with pure oxygen, iron ore is reduced and melted to produce pig iron and slag, and blast furnace gas 4 which sub-stantially does not contain nitrogen is generated from the furnace top.
Dust is removed from blast furnace gas 4 by dust collector 7. The resultant gas, free from dust, is di-verted to different destinations. A portion is supplied to combustion furnace 9, another portion is supplied as temperature control gas 4' to tuyères 2, another portion is utilized in the steelmaking plant, and the remaining portion is supplied to Co2-separating plant 8. The re-sultant CO and H2 gases are used as a synthetic chemical 806(~3 industrial gas. CO2 gas from CO2-separating plant 8 can be supplied as a temperature control gas to preheating gas generation combustion furnace 9 or tuyères 2.
In the operation method described above, h2O 12 and temperature control gas 4' are blown from tuyères 2 to prevent temperature rise at the nose of tuyère caused by blowing of pure oxygen. The blowing rate is controlled to set a theoretical flame temperature at the nose of tuyère to be 2,000 to 2,600C. Pulverized coal blowing from tuyères 2 is used as a substitute for coke. Ac-cording to the present invention, since pure oxygen is blown from tuyères 2, a large amount of pulverized coal can be blown.
More specifically, when the concentration of oxygen blown from tuyères 2 is increased, the amount of pulver-ized coal is increased, as shown in Fig. 2, although the rate varies according to various conditions such as the type of pulverized coal. Upon an increase in concentra-tion of oxygen blown from the tuyères, an amount of gas flowing through the furnace is decreased. For this reason, the gas must be replenished in the amount to compensate for shortage, as shown in Fig. 3. ~ccording to the present invention, blowing of pure oxygen from the tuyères and the preheating gas from the intermediate shaft level allows blowing of a large amount of pulver-ized coal, e.g., 400 kg/ton of pig iron, and preferably 100 to 400 kg~ton of pig iron. In other words, the amount of coke used in the operation can be greatly reduced.
In order to control the amount of latent heat from the blast furnace, 2 top gas from the tuyères and a blowing rate of H2O are controlled to change a fuel ratio~
Preheating gas 5 is used to increase a gas flow within the furnace and to preheat the charge in the fur-nace. Gas 5 can be generated by combusting the blast furnace gas in combustion furnace 9 with oxygen 3'. The blowing rate of preheating gas 5 is determined by consi~
dering the amount of gas generated at a level below the blowing level such that a thermal flow ratio (solid/gas) preferably falls within the range of 0.8 to 1Ø If the thermal flow ratio is excessively low, a large amount of gas must be blown and its calories are wasted. However, if the thermal flow ratio is excessively high, a short-age of calories within the furnace occurs. The tempera-ture in the furnace is then excessively decreased, and a failure to perform satisfactory gas reduction occurs.
As a result, the furnace operation becomes unstahle.
The preheating gas temperature preferably falls within the range of 500 to 1,200C. If the temperature is ex-cessively low, chemical reduction cannot be sufficiently performed. However, if the temperature is excessively high, the solution loss increases. Therefore, the heat balance at the bottom of the furnace is disturbed, and ~80609 _ 9 the furnace operation becomes unstable. In addition, if iron ore reduction rate is high, the preheatins gas temperature can be set to be low. However, if iron ore reduction rate is low, the preheating gas temperature can be set to be high. Therefore, without delaying the reduction reaction, the calories can be effectively utilized. The preheating gas temperature can be con-trolled by changing a ratio of the blast furnace gas recycled from furnace top to 2 According to the operation method described above, pure oxygen is blown and external N2 gas is substan-tially not introduced to the system. Therefore, the blast furnace gas substantially does not contain N2 gas, therefore N2 need not be separated from the blast furnace gas. Only CO2 gas is separated from the blast furnace gas to be used as a synthetic chemical indus-trial gas, as needed. Therefore, the cost of the gas can be greatly reduced.
The temperature rise at the nose of tuyère or its vicinity upon blowing of pure oxygen can be prevented by blowing the blast furnace gas circulated from the fur-nace top. In addition, the preheating gas blown from the intermediate shaft level prevents a shortage of gas flow, thereby stably operating the blast furnace.
Furthermore, since pulverized coal is blown, the amount of coke used in the furnace can be greatly reduced, thereby reducing the operation cost. A required amount 806(;~3 of blast furnace gas is subjected to CO2 separation when it is used as a synthetic chemical industrial gas, thus further reducing the gas cost.
The operation of the blast furnace according to the present invention will be described with reference to Fig. 1.
Iron ore and coke ta coke ratio of 350 kg/T-HM
or Ton-Hot Metal) were charged into a blast furnace (5,000 t-HM/d or Hot Metal/Day), and pure oxygen (349 Nm3/T), a top gas (165 Nm3/T), pulverized coal (300 kg/T-HM = 21 t/H), and steam (3 kg/T) for pre-venting variations in blast furnace gas composition were blown in the furnace. A preheating gas (1,000C, 105 Nm3/T) was blown from the intermediate shaft portion of the blast furnace. In this case, the preheating gas was produced by combusting the top gas (105 Nm3/T) with oxygen (10 Nm3/T).
The composition of the top gas produced by the blast furnace operation described above was 49% of CO, 33.5% of CO~, 9.2% of H2, 0.73% of H2O, and 0.8~ of N2.
The top gas thus substantially does not contain N2 gas.
The blast furnace gas was passed through the dust-collecter, and the gas without dust was diverted to different destinations. A portion (105 Nm3/T) was blown in the combustion furnace, another portion (165 Nm3/T) was blown from the tuyères, another portion (1,080 Nm3/T, 1,726 KcaQ/Nm3) was used in the steel works, and the ~806(~9 remaining portion was subjected to CO2 separation. The resultant CO and H2 gases were used as a synthetic che-mical industrial gas.
Example 2 Fig 4 shows Example 2 of the method of operating the blast furnace according to the present invention.
Blast furnace operation in Fig. 4 differs from that in Fig. 1 in that CO2 gas, H2O (water or steam), or a gas mixture of CO2 and H2O is blown as temperature control gas 4' from tuyères 2. The CO~ gas is a portion ot the C2 gas from CO2~separating plant 8 and is supplied from C2 supply device 10 to tuyères 2. Another portion of the CO2 gas from CO2-separating plant 8 is supplied to combustion furnace 9 to control the temperature of pre-heating gas 5 generated by combusting the top gas.Example 2 preferably follows the same procedures as in Example 1 and obtains the same effect as therein.
Example 2 will be described with reference to Fig. 4 Iron ore and coke ~a coke ratio of 500 kg/T-~
were charged into a blast furnace (5,000 t-HM~d), and pure oxygen (75,000 Nm3/H), CO2 (40,000 Nm3/H), and pulverized coal (100 kg/T-HM = 21 t/H) were blown from the tuyères. A preheating gas (1,000C, 83,000 Nm3/H 27 x 206 XcaQ/H) was blown from the inter-mediate shaft level. The preheating gas was obtained by combusting a blast furnace gas (14,600 Nm3/H) with 1~8~609 oxygen (5,000 Nm3/H), and the temperature of the pre-heating gas was controlled with CO2 (25,000 Nm3/H).
The composition of the blast furnace gas obtained by the above blast furnace operation was 53~ of CO and 47% of CO2. This blast furnace gas substantially does not contain N2 gas. After the gas was passed through the dust-collecter, a gas portion (14,600 Nm3/H) was blown in the combustion furnace, another gas portion (81,000 Nm3/H, 1~590 KcaQ/Nm3) was used in the steelmak-ing plant, and the remaining portion (135rOOO Nm3/h) wagsubjected CO2 separation and used as a synthetic chemi-cal industrial gas. The CO2 gas obtained upon CO2 se-paration was 25,800 Nm3/H. A predetermined amount of gas was used as a preheating gas temperature control gas 15 and a pulverized coal carrier gas.
Claims (9)
1. A method of operating a blast furnace, compris-ing the steps of:
charging a charge including iron ore and coke as major constituents from a furnace top into the blast furnace;
blowing pure oxygen, pulverized coal, and a temper-ature control gas from tuyeres, the temperature control gas being adapted to prevent a temperature rise at the nose of tuyere;
blowing a preheating gas which substantially does not contain nitrogen from an intermediate shaft level to preheat the charge in the blast furnace; and combusting coke with the pure oxygen to melt the iron ore and generating a blast furnace gas which sub-stantially does not contain nitrogen.
charging a charge including iron ore and coke as major constituents from a furnace top into the blast furnace;
blowing pure oxygen, pulverized coal, and a temper-ature control gas from tuyeres, the temperature control gas being adapted to prevent a temperature rise at the nose of tuyere;
blowing a preheating gas which substantially does not contain nitrogen from an intermediate shaft level to preheat the charge in the blast furnace; and combusting coke with the pure oxygen to melt the iron ore and generating a blast furnace gas which sub-stantially does not contain nitrogen.
2. A method according to claim 1, wherein the tem-perature control gas is a gas selected from the group consisting of H2O, CO2, and a gas mixture thereof, and is blown such that a theoretical flame temperature at the nose of tuyère falls within a range of 2,000 to 2,600°C.
3. A method according to claim 1, wherein the tem-perature control gas is a gas generated from a top of the blast furnace and is blown such that a theoretical flame temperature at the nose of tuyère falls within a range of 2,000 to 2,600°C.
4. A method according to claim 1, wherein the preheating gas has a temperature falling within a range of 500 to 1,200°C, and an amount of the preheating gas is controlled such that a thermal flow ratio of solid to gas is set to be 0.8 to 1Ø
5. A method according to claim 1, wherein the pulverized coal is blown in an amount up to 400 kg/ton of pig iron.
6. A method of opera-ting a blast furnace, compris-ing the steps of:
charging a charge including iron ore and coke as major constituents from a furnace top into the blast furnace;
blowing pure oxygen and a temperature control gas from tuyères, the temperature control gas being adaptea to prevent a temperature rise at the nose of tuyère;
blowing a preheating gas which substantially does not contain nitrogen from an intermediate shaft level to preheat the charge in the blast furnace; and combusting coke with the pure oxygen to melt the iron ore and generating a blast gas which substantially does not contain nitrogen.
charging a charge including iron ore and coke as major constituents from a furnace top into the blast furnace;
blowing pure oxygen and a temperature control gas from tuyères, the temperature control gas being adaptea to prevent a temperature rise at the nose of tuyère;
blowing a preheating gas which substantially does not contain nitrogen from an intermediate shaft level to preheat the charge in the blast furnace; and combusting coke with the pure oxygen to melt the iron ore and generating a blast gas which substantially does not contain nitrogen.
7. A method according to claim 6, wherein the temperature control gas is a gas selected from the group consisting of H2O, CO2, and a gas mixture thereof, and is blown such that a theoretical flame temperature at the nose of tuyère falls within a range of 2,000 to 2,600°C.
8. A method according to claim 6, wherein the tem-perature control gas is a gas generated from a top of the blast furnace and is blown such that a theoretical flame temperature at the nose of tuyère falls within a range of 2,000 to 2,600°C.
9. A method according to claim 6, wherein the preheating gas has a temperature falling within a range of 500 to 1,200°C, and an amount of the preheating gas is controlled such that a thermal flow ratio of solid to gas is set to be 0.8 to 1Ø
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60165383A JPS6227509A (en) | 1985-07-26 | 1985-07-26 | Method for operating blast furnace |
| JP165383/85 | 1985-07-26 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1280609C true CA1280609C (en) | 1991-02-26 |
Family
ID=15811342
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000513690A Expired - Lifetime CA1280609C (en) | 1985-07-26 | 1986-07-14 | Method of operating blast furnace |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US4917727A (en) |
| EP (1) | EP0209880B1 (en) |
| JP (1) | JPS6227509A (en) |
| KR (1) | KR920004699B1 (en) |
| CN (1) | CN1007160B (en) |
| AU (1) | AU588043B2 (en) |
| CA (1) | CA1280609C (en) |
| DE (1) | DE3686852T2 (en) |
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| US20020127505A1 (en) * | 2001-01-11 | 2002-09-12 | Hisashi Kobayashi | Oxygen enhanced low nox combustion |
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| ES2566798T3 (en) * | 2002-05-15 | 2016-04-15 | Praxair Technology, Inc. | Combustion with low NOx emissions |
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| US20100146982A1 (en) * | 2007-12-06 | 2010-06-17 | Air Products And Chemicals, Inc. | Blast furnace iron production with integrated power generation |
| US8133298B2 (en) * | 2007-12-06 | 2012-03-13 | Air Products And Chemicals, Inc. | Blast furnace iron production with integrated power generation |
| AT507823B1 (en) * | 2009-01-30 | 2011-01-15 | Siemens Vai Metals Tech Gmbh | METHOD AND APPARATUS FOR PRODUCING RAW IRONS OR LIQUID STEEL PREPARED PRODUCTS |
| CA2755160C (en) * | 2009-03-17 | 2014-02-18 | Fernand Didelon | Method for recirculating blast furnace gas, and associated device |
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| DE102009022510B4 (en) * | 2009-05-25 | 2015-03-12 | Thyssenkrupp Industrial Solutions Ag | Process for the simultaneous production of iron and a raw synthesis gas containing CO and H2 |
| JP4697340B2 (en) * | 2009-05-29 | 2011-06-08 | Ｊｆｅスチール株式会社 | Blast furnace operation method |
| WO2011039809A1 (en) * | 2009-09-30 | 2011-04-07 | 新日鉄エンジニアリング株式会社 | Method for separating and collecting carbon dioxide from blast furnace gas |
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| AU2010324338B2 (en) * | 2009-11-24 | 2014-06-26 | Central Iron & Steel Research Institute | Method for iron-making with full oxygen and hydrogen-rich gas and equipment thereof |
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| CN102759419A (en) * | 2011-04-28 | 2012-10-31 | 宝山钢铁股份有限公司 | Determination method for heat redundancy in blast furnace |
| JP6127299B2 (en) | 2011-09-27 | 2017-05-17 | 株式会社トキワ | Liquid cosmetic container |
| US20150068364A1 (en) | 2011-12-27 | 2015-03-12 | Hyl Technologies, S.A. De C.V. | Blast furnace with top-gas recycle |
| US9605326B2 (en) | 2012-07-03 | 2017-03-28 | Hyl Technologies, S.A. De C.V. | Method and system for operating a blast furnace with top-gas recycle and a fired tubular heater |
| GB2513185A (en) * | 2013-04-19 | 2014-10-22 | Siemens Vai Metals Tech Gmbh | Blast furnace plant |
| CN106103746B (en) * | 2014-03-26 | 2018-07-31 | 杰富意钢铁株式会社 | The operating method of oxygen blast furnace |
| KR20180119713A (en) * | 2014-08-27 | 2018-11-02 | 제이에프이 스틸 가부시키가이샤 | Method for injecting pulverized coal into oxygen blast furnace |
| US10961596B2 (en) * | 2016-02-05 | 2021-03-30 | Nippon Steel Corporation | Method for supplying hydrogen-containing reducing gas to shaft part of blast furnace |
| CN105671229B (en) * | 2016-02-29 | 2018-02-23 | 神雾科技集团股份有限公司 | Oxygen blast furnace and gas-based shaft kiln Joint Production system and combine production method |
| CN105586451A (en) * | 2016-02-29 | 2016-05-18 | 北京神雾环境能源科技集团股份有限公司 | Joint production system and joint production method of oxygen blast furnace and gas-based shaft kiln |
| CN105586454A (en) * | 2016-02-29 | 2016-05-18 | 北京神雾环境能源科技集团股份有限公司 | Joint production system and joint production method of oxygen blast furnace and gas-based shaft kiln |
| CN105671228B (en) * | 2016-02-29 | 2018-02-27 | 神雾科技集团股份有限公司 | Oxygen blast furnace and gas-based shaft kiln Joint Production system and combine production method |
| CN105734190B (en) * | 2016-02-29 | 2018-09-07 | 神雾科技集团股份有限公司 | Oxygen blast furnace and gas-based shaft kiln Joint Production system and combine production method |
| CN105586452B (en) * | 2016-02-29 | 2018-09-07 | 神雾科技集团股份有限公司 | Oxygen blast furnace and gas-based shaft kiln Joint Production system and combine production method |
| CN105586450B (en) * | 2016-02-29 | 2019-02-01 | 神雾科技集团股份有限公司 | Oxygen blast furnace and gas-based shaft kiln Joint Production system and combine production method |
| CN105586453A (en) * | 2016-02-29 | 2016-05-18 | 北京神雾环境能源科技集团股份有限公司 | Joint production system and joint production method of oxygen blast furnace and gas-based shaft kiln |
| CN105586455A (en) * | 2016-02-29 | 2016-05-18 | 北京神雾环境能源科技集团股份有限公司 | Joint production system and joint production method of oxygen blast furnace and gas-based shaft kiln |
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-
1985
- 1985-07-26 JP JP60165383A patent/JPS6227509A/en active Pending
-
1986
- 1986-07-11 KR KR1019860005618A patent/KR920004699B1/en not_active IP Right Cessation
- 1986-07-14 CA CA000513690A patent/CA1280609C/en not_active Expired - Lifetime
- 1986-07-16 AU AU60232/86A patent/AU588043B2/en not_active Ceased
- 1986-07-21 DE DE8686109999T patent/DE3686852T2/en not_active Expired - Fee Related
- 1986-07-21 EP EP86109999A patent/EP0209880B1/en not_active Expired - Lifetime
- 1986-07-26 CN CN86105560A patent/CN1007160B/en not_active Expired
-
1988
- 1988-11-22 US US07/279,252 patent/US4917727A/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| DE3686852T2 (en) | 1993-02-25 |
| US4917727A (en) | 1990-04-17 |
| JPS6227509A (en) | 1987-02-05 |
| DE3686852D1 (en) | 1992-11-05 |
| EP0209880A2 (en) | 1987-01-28 |
| EP0209880A3 (en) | 1988-08-03 |
| KR870001314A (en) | 1987-03-13 |
| KR920004699B1 (en) | 1992-06-13 |
| EP0209880B1 (en) | 1992-09-30 |
| AU6023286A (en) | 1987-01-29 |
| CN1007160B (en) | 1990-03-14 |
| CN86105560A (en) | 1987-02-04 |
| AU588043B2 (en) | 1989-09-07 |
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